1. Field of the Invention
The invention relates to a method of producing a mixed gas from the process gas of a continuously operating gasifier and a discontinuously accruing off-gas of an oxygen blowing converter, e.g. during a process for refining pig iron with oxygen, as well as to a plant for carrying out this method.
In particular, this invention is designed for metallurgical plants having reduction and melt-down gasification furnaces for recovering pig iron as well as refining furnaces for converting pig iron into steel.
Normally, separate means for collecting, dedusting and deacidifying are necessary for the accruing process gases, e.g., for the reduction gas or top gas from the reduction plants, and for the converter off-gases. This is because the top gas originating from the reduction plant has a higher pressure, approximately from 2 to 5 bar, and a temperature of from 300.degree. to 400.degree. C., while the converter off-gas has a lower pressure of 0.01 bar and a temperature of approximately 1100.degree. C. Usually it is complex to use the converter off-gases with respect to their content of chemical energy (CO-content and H.sub.2 -content). Therefore, in many cases these gases are burned off, thus causing a burden on the environment.
2. Description of the Related Art
According to Australian Pat. No. 540,666 it is already known to feed refinery gases from low pressure systems into a heating gas network operated at a higher pressure, wherein the refinery gases are compressed to the higher pressure prevailing in the heating gas network in a gas jet compressor by using the gases derived from the refinery and intended for the heating gas network as power gas and subsequently admixing them. This system is not suited for low pressure gases which, when occurring discontinuously, may contain oxygen.